Segmented binary rate multiple-beam display system

ABSTRACT

A character generator system produces a visual vector display in response to digital vector commands. A plurality of cathode ray beams impinge upon the display screen in a matrix array. The control grid has separate control elements which selectively control the intensity of each of the beams. The deflection system positions the matrix array of cathode ray beams to different locations on the display screen. A segmented binary rate multiplier responds to the digital vector commands to produce intensity control signals which are applied to the control elements to selectively intensify the cathode ray beams to produce a vector segment having a starting point and a terminating point and which extends across the matrix array. The binary rate multiplier also produces deflection signals which position the array so that the starting point of the vector segment across a new array coincides with the terminating point on the previous array.

United States-Patentm1 Eichelberger 1 May 8, 1973 [541 SEGMENTED BINARY RATE MULTIPLE-BEAM DISPLAY SYSTEM [75] Inventor: William Ernest Eichelberger,

Raleigh, NC.

[73] Assignee: Corning Glass Works, Corning,

[22] Filed: June 7, 1971 [21] Appl. N0.: 150,636

[52] US. Cl. ..340/324 AD, 315/18 Primary Examiner-David L. Trafton Anomey-Clarence R. Patty, Jr., Walter Zebrowski and Woodcock, Washburn, Kurtz & Mackiewicz [57] ABSTRACT A character generator system produces a visual vector display in response to digital vector commands. A plurality of cathode ray beams impinge upon the display screen in a matrix array. The control grid has separate control elements which selectively control the intensity of each of the beams. The deflection system positions the matrix array of cathode ray beams to different locations on the display screen. A segmented binary rate multiplier responds to the digital vector commands to produce intensity control signals which are applied to the control elements to selectively intensify the cathode ray beams to produce a vector segment having a starting point and a terminating point and which extends across the matrix array. The binary rate multiplier also produces deflection signals which position the array so that the starting point of the vector segment across a new array coincides with the terminating point on the previous array.

5 Claims, 4 Drawing Figures SHEET 1 [IF 4 57 X 54 55 Y D/A C 3s CONVERTER 1 g H St CONVERTER 5395 WOID mi; 37 F UPIDOwN 35 BIT DONNI, CLOCK COUNTER LATCH 5l coum'en U/D U/D (ONTROL I I CONTROL 0P5 1 OF IOF7 3! DECODE 33 I (one cove 9722mm J P W Tesl 5e 5, 49 48 50 g'flfi LoNT. UID Er 49 34 43 35 '3 BIT BRM 6 3 B T BRM nun/on GfiTmG 38 up comm: 3, am: lol: C-n'rme 44 3,9 I I I is}! MOD 5 FULL FULL 4' $11 Hulk MOD 7 & up coumc 8 0R 7 UP coumea RESET 2 3O T -ijY Dj l J FULL B 45 f- 3 02 40 2? f w 28 l 2 46 4 IO BIT BRM MOD mm 10 an BRM moo/o2 Gnrms yo COUNTER union GRTING- I I l 29 I l ex #23 AY L v i g 25 A SCI l S/ P QCONVERTER 22 24 26 PATENTEDHT'TY H373 3 732,559

SET DIRECTIONS FOR M005, MOD? AND MOD I024 UP/DOWN COUNTER START MOD 1024 r62 COUNTER 29 IS 55 YES MOD I024 N0 66 COUNTER FULL STOP MOD I024 COUNTER 54 IS 57 MOD 5 TURN ON COUNTER 55 CRT GRIDS FOR 1d MOD 7 m COUNTER miifjmY. LL LL FULL START MOD 8 J68 COUNTER COUNT INTO MAJOR 69 MOD 5 a MOD 7 pl RESET MOD 5 a MOD 7 72 1s v MOD I024 COUNTER FULL m READY FOR NEW VECTOR SEGMENTED BINARY RATE MULTIPLE-BEAM DISPLAY SYSTEM.

CROSS REFERENCE TO COPENDING APPLICATION This application relates to subject matter disclosed in application Ser. No. 103,257, filed Dec. 31, 1970, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to digital display systems and more particularly to a digital character generator system having a multiple beam cathode ray tube which can be used to generate a vector display.

Computer systems having a graphic display device have come into widespread use. One example of such systems is the Coming 904 Time-Sharing Terminal used in a system configured by Corning Glass Works, Corning, N.Y. Such systems have a display device which has the capability for displaying both alphanumeric and vector displays. The generation of vector commands by the central computer in such a system is described in copending application Ser. No. 103,257, filed Dec. 31, 1970, Wood al, a1. now abandoned. Such systems have successfully used binary rate multipliers to convert input vector commands to deflection voltages for a cathode ray beam. In a binary rate multiplier the count in a digital counter is converted to analog deflection signals which position a cathode ray beam to trace out the vector specified by the input command.

Display devices in which a plurality of cathode ray beams impinge on the display screen have recently been used as character generators. One example of such a device is the Siemens Multi-beam Cathode Ray Tube. These devices are particularly suitable for displaying alphanumeric characters. By selectively inten-- SUMMARY OF THE INVENTION In accordance with an important aspect of this invention, a display device in which a plurality of cathode ray beams impinge on the display screen in a matrix array has the capability for displaying vectors. This capability is provided by a segmented binary rate multiplier. This produces vector segments each of which can be drawn by the selective intensification of the plurality of cathode ray beams.

In a specific embodiment of the invention the binary rate multiplier responds to digital input commands to produce intensity control signals which are applied to the control elements of a control grid. These selectively intensify the cathode ray beams to produce a vector segment having a starting point, and a terminating point, and which extends across the matrix array. The binary rate multiplier produces a deflection signal which moves the entire matrix array to a new position on the display screen. This new position is such that the starting point of the next vector segment coincides with the terminating point of the previous vector segment. The generation of the vector segments continues until the entire vector specified by the input vector command has been drawn on the display screen.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows a block diagram of the display systems of this invention;

FIG. 1A is a control diagram;

FIG. 2A shows a binary rate multiplier; and

FIG. 2B shows the multiple beam cathode ray tube.

DESCRIPTION OF A PARTICULAR EMBODIMENT Referring to FIG. 1 the display system includes a cathode ray tube 11. This tube is of the type which produces a plurality of cathode ray beans which impinge on the display screen in a matrix array. The embodiment being described produces beams which impinge upon the display screen in a 5 X 7 matrix indicated by the dots 12-16 and others. By selectively intensifying the cathode ray beams, the dots in the matrix appear as bright spots on the display screen. This selective intensification can be used to display an alphanumeric character on the display screen.

In accordance with this invention, this 5 X 7 array of cathode ray beams is used to produce vector segments. For example, the dots on the straight line including the dots l2 and 15 are selectively intensified to produce the vector segment which has a starting point at the dot 12 and a terminating point at the'dot 15. The vector segment extends across the matrix array between these two points. After this vector segment has been drawn,

the matrix array is moved to a new position by deflection means 17, typically deflection coils. These coils are energized by deflection signals which position the matrix array to a new position which includes the array of dots l5, l8, 19, 20, 21 and others. With the matrix array in this new position, the cathode ray beams are again selectively intensified to draw the vector segment which includes the dots 15 and 20. The matrix array is positioned so that the starting point for the second vector segment coincides with the terminating point for the first vector segment, namely on the dot 15. Then, the array of cathode ray beams is re-positioned to draw a third vector segment. By drawing a number of segments, a complete vector will be drawn across the face of the tube. Because of the persistance of the phosphor, this will appear as a continuous line on the display screen. In a system such as the Coming 904 the displayed vector is stored by the photochromic image storing capability of the tube.

The circuitry for performing this operation will now be described. It will be described as an improvement on a system such as the Corning 904 System. In such a system vectors are drawn in response to digital input commands generated by a central computer. Specifically, the computer generates two ASCII characters to specify the incremental horizontal magnitude of the vector, AX, and two ASCII characters to specify the incremental vertical magnitude of the vector, AY. These four ASCII characters set into the serial to parallel converter 22 from which they are transferred in parallel to the AX register 23 and to the AY register 24.

The sign, or direction of the vector in the X direction is set into the bit position 25 of the register and the sign of the vector in the Y direction is set into the bit position 26. In the example of FIG. 1, the vector was drawn in the first quadrant, i.e. +AX and +AY. The direction or quadrant of the vector can be changed by changing the sign of either or both AX and AY.

In the embodiment being described, the digital vector commands can specify a vector having an X and a Y magnitude of up to 1,024 terminal plotting screen increments. (TPSI) (In actual practice, one TPSI is approximately 0.01 1 inches so that vectors up to l 1 inches long can be drawn on the display screen.) Binary rate multipliers convert the commands in the AX register 23 and the AY register 24 to signals controlling the intensification of the cathode ray beam and to signals controlling the deflection of the array.

The binary rate multiplier 27 converts the A X commands and the binary rate multiplier 28 converts the AY commands. These operate under control of the MOD 1,024 counter 29. This counter is started when the vector commands are set into the registers 23 and 24. The counter produces pulse outputs from the plurality of stages. That is, the first stage produces 512 pulses, the second state 256 pulses, the third stage 128 pulses, and the last stage produces 1 pulse. These pulse outputs are applied to the 10 bit binary rate multipliers 27 and 28, which are selectively enabled by the vector command in the AX register 23 and the AY register 24. The outputs of these binary rate multipliers are applied to counters 30-33.

Binary rate multipliers 34 and 35 decode the count standing in counters 30 and 32 and supply clock pulses to the major counters 36 and 37.

A pulse circuit 38 produces a pulse output when the Mod counter 30 is full, that is when it produces its last pulse. Similarly, pulse circuit 39 produces an output when the Mod 7 counter 32 is full. Pulse circuit 40 produces an output when the Mod l,024 counter 29 is full. All of these pulses are applied through OR circuit 41 to the time delay 42. The time delay 42 provides a time interval during which the intensity control signals are applied to the cathode ray display device.

The binary rate multipliers 34 and 35 count pulses from the Mod 8 counter 43. When the Mod 8 counter 43 has counted to a full eight counts, the pulse circuit 44 produces an output which resets counters 30 and 32 and which acts through OR gate 45 and start-stop control 46 to restart the Mod 1024 counter 29.

In accordance with this invention, the vector generation is segmented. Vector segments are traced out by applying intensity control signals to the control elements of a control grid 47 of the cathode ray display device. The control grid 47 has individual control elements for controlling the intensity of each of the 35 electron beams.

The intensity control signals are produced by the decoding circuit 48. The decoding circuit 49 decodes the count in the counter 31 to convert it to a signal on one of five lines. Similarly the circuit 50 converts the count in counter 33 to a signal one of seven lines. The output of the decoding circuit 48 sets selected bits of the 35 bit latch 51. These act through gates 52-54, and others, to produce intensity control signals which trace out a vector segment. For example, the vector segment between the dots 12 and 15 is produced by selective intensification of the five electron beams producing the dots in this segment.

The major counters 36 and 37 containflcounts indicating the major deflection of an array. During the time interval Td no pulses are applied to these counters.

Note that when the signs of Ax and Ay are negative, the counters 31 and 33 are set to operate in the reverse counting direction. In this case the AND gates 58 and 59 are enabled by the start pulse to set a count of five into the counter 31 and a count of seven into the counter 33. In this case the counters count in the reverse direction and the operation is the same as that previously described when the counters are counting in the up, or forward direction.

The operation of the system can be better understood with reference to the control diagram FIG. 1A. This depicts the sequence of operation of the system. As indicated at 60 the vector characters are loaded into the registers 23 and 24 and sign bits are loaded into the bit locations 25 and 26. As indicated at 61 the sign bits set the directions of counting for the counters 31, 33, 36 and 37. Concurrently, as indicated at 62 the Mod 1024 counter 29 is started by a start pulse which is produced when the vector characters have been set into the converter 22. The Mod 1024 counter 29 counts a total of 1,024 pulses which are sufficient to trace a vector completely across the screen of the display device 11. In most instances the vector will be shorter than 1,024 TPSI.

At 63 there is indicated a test to determine whether the Mod 1024 counter is full. The counter 29 is running as long as the counters 30 and 32 are not full. The determinations of whether these counters are full are indicated at 64 and 65. When either of these counters .becomes full, the Mod I024 counter 29 is stopped, this step being indicated at 66 in the control diagram. At this point the control grids 47 are turned on for the time period Td to trace out one vector segment on the screen of the display device. This step is indicated at 67. At the end of this time period the Mod 8 counter 43 is started. The starting of the Mod 8 counter is indicated at 68. Pulses from this counter are applied, through binary rate multipliers 34 and 35 to the major counters 36 and 37. A number of pulses equal to the deflection in the x and y direction are set into the major counters. Supplying pulses to the major counters 36 and 37 is the step 69 in the control diagram.

The counts in counters 36 and 37 are converted into analog deflection voltages which position the matrix array on the screen. Pulses are supplied to the major counters until the Mod 8 counter is full, a determination indicated at 70 in the control diagram. When Mod 8'counter 43 is full, the Mod 5 counter 30 and the Mod 7 counter 32 are reset as indicated at 71. Step 72 in the control diagram indicates a determination of whether the Mod 1024 counter 29 is full. If it is not, the foregoing steps are repeated to trace out another line segment of the vector specified by the input vector. When the Mod 1024 counter 29 has counted through a complete cycle, the system is ready to receive another input vectOl'.

FIGS. 2A and 2B show certain portions of the system in more detail in order to aid in understanding the invention. FIG. 2A shows a typical binary rate multiplier. In particular, the binary rate multiplier 27 and the Mod 1024 counter 29 are shown in more detail. It will be understood that other binary rate multipliers and Mod counters are similar.

Referring to FIG. 2A the input to the system is four serial ASCII characters applied to the serial to parallel converter 22. (ASCII is an acronym for American Standard Communications Information Interchange and it denotes a common coding for control characters.)

The characters are counted by the character counter 200 which transfers the first five bits of the first character into the five left hand bit positions of the X deflection register 23. The first five bits of the second character are gated into the five right hand bit positions of the X deflection register 23. (Each ASCII character has seven usable bit positions. Five bit positions are used for vector magnitude and one bit position is used to denote the sign of the vector, that is whether it is positive or negative.)

The third and fourth ASCII characters specify the Y deflection and are set into the Y deflection register which is not shown in FIG. 2A.

When the serial to parallel converter 22 has received four ASCII characters, a start pulse is produced; The start pulse sets flip-flop 201 which acts through NAND gate 202 to start the production of clock pulses. The clock pulses from clock generator 203 pass through AND gate 204 to the Mod 1,024 counter 29.

This counter includes the flip-flop stages 205-214. The operation of such a counter is well-known. The stage 205 is toggled 512 times, producing 512 output pulses; the stage 206 is toggled 256 times, producing 256 output pulses, the stage 207 is toggled 128 times; and the stage 214 is toggled once. When the stage 214 is toggled, a stop pulse is produced. The result is that the various stages of the counter 29 produce a total of 1,024 pulses which are selectively gated by the gates 215-218, and other gates, to produce pulses proportional in number to the magnitude of the horizontal deflection. For example assume the horizontal deflection is AX= 129 TPSI. The AND gates 216 and 217 will be open. One hundred twenty eight pulses from stage 206 will pass through AND gate 216 and one pulse from stage 214 will pass through AND gate 218. The total of 129 pulses is applied through OR gate 219 to the counters 30 and 31.

Referring to FIG. 2B, the cathode ray display device 11 is of a type which includes an area cathode 220. This produces a large number of electrons which are collimated into separate beams by the control grid 37. The control grid 37 includes control elements 221,222,223 and others, one control element for each beam in the array. Each of the control elements is of conductive metal which is plated through a hole in in an insulator. When an intensity control signal is applied .to the control element, it produces an intensified beam. For example, beam is intensified by applying such a signal to the control element 221.

As is usual in these types of devices, the control cylinder 224 is part of an electron lens system for focusing the beams. The deflection means 17 includes an X deflection coil 225 and a Y deflection coil 226.

While a particular embodiment has been shown and described, modifications will be apparent to those skilled in the art. The appended claims, are, therefore, intended to cover any such modifications.

What is claimed is:

l. A system for producing a visual vector display in response to digital vector commands comprising:

a cathode ray display device of the type producing a plurality of cathode ray beams which impinge on 5 said display screen in a matrix array,

binary rate multipliers responsive to said digital input commands for producing pulses proportional in number to the horizontal and vertical length of said visual vector,

means for segmenting said pulses into groups each containing a number of pulses proportional to the horizontal and vertical length of a vector segment across said matrix array,

a decoder responsive to each group of pulses for producing intensity control signals which selectively intensify said cathode ray beam to produce a vector segment, and

means responsive to said pulses for producing deflection signals which position said matrix array to suecessive positions which link the vector segments produced across adjacent matrix arrays.

2. A system for producing a visual vector display in response to digital vector commands comprising:

25 a cathode ray display device having,

a display screen,

a source of a plurality of cathode ray beams which impinge on said display screen in a matrix array,

a control grid for selectively controlling the inten- 30 sity of each of said beams,

deflection means for positioning said matrix array of cathode ray beams on said display screen,

means for producing intensity control signals, said control signals being applied to said control grid for selectively intensifying said cathode ray beams to produce a vector segment having a starting point, a terminating point, and extending across said matrix array, and

means for producing deflection signals, said deflection signals being applied to said deflection means for positioning said matrix array to positions at which the starting point of the new vector segment coincides with the terminating point of the previ- 0118 vector segment.

3. The system recited in claim 2 wherein said means for producing deflection signals comprises:

an x deflection register receiving a portion of each vector command specifying horizontal movement,

a y deflection register for receiving a portion of each command specifying vertical vector movement, means connected to said J: deflection register for producing pulses proportional in number to the magnitude of said horizontal deflection, and

5 means connected to the output of said y deflection ing a y deflection signal, said J: and y deflection tal deflection or the vertical deflection exceed the signals being applied to said deflection means in limits OfSflid matrix y, and i said cathode ray display device. gating means responsive to said time delay means for 5. The system recited in claim 3 further comprising: applying said intensity control signals to said contime delay means actuated each time pulses propor- E for the Perlod of Sald ytional in number to the magnitude of the horizon- 

1. A system for producing a visual vector display in response to digital vector commands comprising: a cathode ray display device of the type producing a plurality of cathode ray beams which impinge on said display screen in a matrix array, binary rate multipliers responsive to said digital input commands for producing pulses proportional in number to the horizontal and vertical length of said visual vector, means for segmenting said pulses into groups each containing a number of pulses proportional to the horizontal and vertical length of a vector segment across said matrix array, a decoder responsive to each group of pulses for producing intensity control signals which selectively intensify said cathode ray beam to produce a vector segment, and means responsive to said pulses for producing deflection signals which position said matrix array to successive positions which link the vector segments produced across adjacent matrix arrays.
 2. A system for producing a visual vector display in response to digital vector commands comprising: a cathode ray display device having, a display screen, a source of a plurality of cathode ray beams which impinge on said display screen in a matrix array, a control grid for selectively controlling the intensity of each of said beams, deflection means for positIoning said matrix array of cathode ray beams on said display screen, means for producing intensity control signals, said control signals being applied to said control grid for selectively intensifying said cathode ray beams to produce a vector segment having a starting point, a terminating point, and extending across said matrix array, and means for producing deflection signals, said deflection signals being applied to said deflection means for positioning said matrix array to positions at which the starting point of the new vector segment coincides with the terminating point of the previous vector segment.
 3. The system recited in claim 2 wherein said means for producing deflection signals comprises: an x deflection register receiving a portion of each vector command specifying horizontal movement, a y deflection register for receiving a portion of each command specifying vertical vector movement, means connected to said x deflection register for producing pulses proportional in number to the magnitude of said horizontal deflection, and means connected to the output of said y deflection register for producing pulses proportional in number to said vertical deflection.
 4. The system recited in claim 3 wherein said means for producing deflection signals further comprises: an x counter for counting said pulses proportional to horizontal deflection, a first digital-to-analog converter connected to said x counter for producing an x deflection signal, a y counter for counting said pulses proportional in number to vertical deflection, a second digital-to-analog converter connected to the output of said y deflection counter for producing a y deflection signal, said x and y deflection signals being applied to said deflection means in said cathode ray display device.
 5. The system recited in claim 3 further comprising: time delay means actuated each time pulses proportional in number to the magnitude of the horizontal deflection or the vertical deflection exceed the limits of said matrix array, and gating means responsive to said time delay means for applying said intensity control signals to said control grid for the period of said time delay. 